Rifamycin derivative that inhibits bacterial RNA polymerase (same mechanism as rifampicin) but is not absorbed from the GI tract — provides exclusively luminal antibacterial activity. No systemic effects or drug interactions.
At a glance
Class
Non-Absorbable Rifamycin Antibiotic
Storage
Store at room temperature below 30°C
Dosing
Used for hepatic encephalopathy (reduces ammonia-producing bacteria), small inte
Off-label for hepatic encephalopathy and chronic GI bacterial issues
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Safety
Clinical response (stool quality, encephalopathy grade)Ammonia levels (hepatic encephalopathy)
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Interactions
No documented interactions.
FAQs
Frequently asked questions
›What is Rifaximin?
Rifaximin is a non-absorbable rifamycin antibiotic used in pets. Rifamycin derivative that inhibits bacterial RNA polymerase (same mechanism as rifampicin) but is not absorbed from the GI tract — provides exclusively luminal antibacterial activity. No systemic effects or drug interactions.
›What is Rifaximin used for in pets?
Rifaximin is used in veterinary medicine for: Used for hepatic encephalopathy (reduces ammonia-producing bacteria), small inte; Off-label for hepatic encephalopathy and chronic GI bacterial issues.
›What is the Rifaximin dose for dogs?
For dogs, Rifaximin is typically dosed as follows — Used for hepatic encephalopathy (reduces ammonia-producing bacteria), small inte: 10–25 mg/kg PO q8–12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Rifaximin dose for cats?
For cats, Rifaximin is typically dosed as follows — Off-label for hepatic encephalopathy and chronic GI bacterial issues: 10–15 mg/kg PO q12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Rifaximin need a prescription?
Yes. Rifaximin is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →References
References
The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.
Textbooks & handbooks — 5
- Plumb's Veterinary Drug Handbook
- Withrow & MacEwen's Small Animal Clinical Oncology
- Merck Veterinary Manual
- NRC Nutrient Requirements of Dogs and Cats
- Veterinary Pharmacology and Therapeutics (Riviere & Papich)
Clinical guidelines & consensus — 4
- ASPCA Animal Poison Control Center Guidelines
- AAHA Diabetes Management Guidelines
- ASPCA Poison Control Guidelines
- RECOVER CPR Guidelines
Journals & peer-reviewed studies — 2
- EPIC Study (J Vet Intern Med 2016)
- JVIM FAT CAT Study
Regulatory & approvals — 1
- CDSCO Veterinary Drug Approval Registry (1969–2026)
Databases — 1
- Washington State University VCPL MDR1 Database